GM Screen clips for 28mm scale miniatures

I got an email recently saying that a certain miniature printing service was offering GM screen clip bases so that you could attach your miniature to a GM screen and use it to track initiative, etc. I figured I'd try my hand at an open source version of that.

Each of these clips are numbered 1-5 and are designed to hold any miniature that has a 25mm = 1in diameter base - so they should work for almost all character minis in a game of D&D. The distance between prongs of the clip was callibrat